Savoldi Fabio, Svanetti Lorenzo, Tsoi James K H, Gu Min, Paganelli Corrado, Genna Francesco, Lopomo Nicola F
Orthodontics, Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Sai Ying Pun, Hong Kong SAR.
Orthodontics, Dental School, Department of Medical Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Piazzale Spedali Civili 1, 25123, Brescia, Italy.
J Mech Behav Biomed Mater. 2022 Aug;132:105272. doi: 10.1016/j.jmbbm.2022.105272. Epub 2022 May 14.
A continuous positive airway pressure (CPAP) mask is a respiratory ventilation method used for treating breathing disorders including respiratory failure and obstructive sleep apnoea (OSA). The forces applied by a CPAP mask may affect facial development and lead to pressure ulcers. In an experimental setting, the magnitude and the distribution of the contact pressures developed by a CPAP mask on the face were investigated for providing information aiming at optimizing the design of the device.
A nasal CPAP mask with forehead support was placed via its headgear straps on a rigid phantom head and then a controlled load was incrementally applied via a mechanical testing system (5848 Micro Tester, Instron), up to 4 maximum levels of exerted force, namely 5 N, 10 N, 15 N, and 20 N. Real-time pressure mapping was realized by means of sensor matrixes (I-Scan System, Tekscan) applied on the facial surface in four regions (forehead, nasal bridge, zygoma, and maxilla). The data were then transferred on a virtual model created by 3D scans of both the CPAP mask and the phantom head used in the experiments.
At increasing applied force, increases in average contact pressure were present at the zygomatic region (1-8 kPa), nasal bridge (12-14 kPa), and forehead (13-29 kPa), while the maxillary region showed relatively stable values (9 kPa). Despite the overall increase in average contact pressure with increasing applied force, no direct proportionality was present. Contact areas did not show clear increments, despite force may redistribute on a larger area, as sensors did not cover the entire mask perimeter. Peak contact pressure values were somehow affected by pressure concentrations that led to saturation in some areas of the sensors (up to 2% of the sensels).
The CPAP mask exerts pressures that may be not uniformly distributed on the face of a subject. This information underlines the clinical importance of assessing both the pressure exerted and the areas that are interested by the mask contact, so as to optimise the CPAP masks design for obtaining a good compromise between ventilation performance and reduction of possible side effects on living tissues.
持续气道正压通气（CPAP）面罩是一种用于治疗包括呼吸衰竭和阻塞性睡眠呼吸暂停（OSA）在内的呼吸障碍的呼吸通气方法。CPAP面罩施加的力可能会影响面部发育并导致压疮。在实验环境中，研究了CPAP面罩在面部产生的接触压力的大小和分布，以提供旨在优化该设备设计的信息。
将带有前额支撑的鼻CPAP面罩通过其头带放置在刚性仿人头模型上，然后通过机械测试系统（5848 Micro Tester，英斯特朗公司）逐步施加可控负载，直至达到4个最大施加力水平，即5 N、10 N、15 N和20 N。通过应用于面部四个区域（前额、鼻梁、颧骨和上颌骨）的传感器矩阵（I-Scan系统，泰科森公司）实现实时压力映射。然后将数据传输到通过对实验中使用的CPAP面罩和仿人头模型进行3D扫描创建的虚拟模型上。
随着施加力的增加，颧骨区域（1 - 8 kPa）、鼻梁（12 - 14 kPa）和前额（13 - 29 kPa）的平均接触压力增加，而上颌区域显示出相对稳定的值（9 kPa）。尽管随着施加力的增加平均接触压力总体上有所增加，但不存在直接的比例关系。尽管力可能会在更大的区域重新分布，但接触面积并未显示出明显增加，因为传感器未覆盖整个面罩周边。峰值接触压力值在某种程度上受到压力集中的影响，导致传感器某些区域出现饱和（高达2%的传感单元）。
CPAP面罩施加的压力可能不会均匀分布在受试者面部。该信息强调了评估施加的压力以及面罩接触所涉及区域的临床重要性，以便优化CPAP面罩设计，在通气性能和减少对活体组织可能的副作用之间取得良好平衡。
